From an article in Strings magazine:
The biggest mistake musicians make is denying they feel anxiety, says Patricia Thornton, a New York psychologist who specializes in anxiety disorders. “If you tell yourself not to be anxious and feel anxious anyway, you’ll feel even worse,” she explains. “Denial makes the thought more resistant.”
The solution: Embrace the anxiety.
“Instead of trying to relax, energize yourself,” Thornton says. “Get your heart-rate up. If you’re performing with other people, cheer each other on. Then you can attribute that elevated heart rate to excitement rather than anxiety.”
Read on here.